Modeling Waffle Shape of Cone
You may model it using poke and bevel tools.

Select the faces you want to put the pattern on and hide the rest of the mesh with Shift+H. Press Alt+P to poke faces. Select vertical edges (select one of them, go to Select--&gt;Select Similar--&gt;Face Angles), then dissolve them (except for top and bottom ones) with X--&gt;Dissolve Edges. Do the same with horizontal ones. You now have the pattern base.

Select all the faces, press Ctrl+B and drag the mouse to achieve the desired patern's thickness. Inverse the selection with Ctrl+I. Extrude and scale faces inwards (E,I,Shift+Z).

Unhide everything (Alt+H), select the pattern except for very top and bottom edges. Go to edge selection and press Shift+E to crease it.


Finally, you may bake created pattern to the low-poly version of your ice cone (bake normals) and apply it as a normal texture.